Problem 231 - A Complete Resource Book in Chemistry for JEE Main

Question

Sodium ethoxide has reacted with ethanoyl chloride. The compound that is produced in the above reaction is: (a) 2-Butanone (b) Ethyl chloride (c) Ethyl ethanoate (d) Diethyl ether

Step-by-Step Solution

Answer

The compound produced is (c) Ethyl ethanoate.

Step 1: Recognize the Reaction Type

Sodium ethoxide (C₂H₅ONa) is a base and ethanoyl chloride (CH₃COCl) is an acyl chloride. The reaction between an acyl chloride and an alcohol (or its alkoxide) is a nucleophilic acyl substitution that forms an ester.

Step 2: Write the Balanced Chemical Equation

The reaction between sodium ethoxide and ethanoyl chloride can be represented as:\[C_2H_5ONa + CH_3COCl \rightarrow CH_3COOC_2H_5 + NaCl\]This equation shows that the nucleophilic oxygen of the ethoxide ion attacks the carbonyl carbon of ethanoyl chloride, leading to the formation of ethyl ethanoate and sodium chloride.

Step 3: Identify the Product Based on the Reaction

From the chemical equation, the main organic product formed is ethyl ethanoate (CH₃COOC₂H₅), which is an ester.

Key Concepts

Sodium Ethoxide

Sodium ethoxide is an important compound often encountered in organic chemistry. It is represented chemically as \( C_2H_5ONa \). It consists of an ethoxide ion \( (C_2H_5O^-) \), which is a deprotonated form of ethanol, paired with a sodium ion \( (Na^+) \). Sodium ethoxide is a strong base, which makes it highly reactive, particularly in reactions that involve proton transfers.

One of its typical uses is in nucleophilic substitution reactions. Here, the ethoxide ion acts as a nucleophile. In such a role, it will seek out and attack electrophilic centers present in other molecules, such as carbon atoms that bear a slight positive charge. This attack is often a key step in transforming molecules into new compounds.

Key properties of sodium ethoxide are:

• Strong nucleophilic character
• Effective in promoting ester formation
• Commonly used in synthetic organic chemistry

Ethanoyl Chloride

Ethanoyl chloride, also known as acetyl chloride, is a simple acyl chloride represented by the formula \( CH_3COCl \). This compound is notable for its reactivity, particularly towards nucleophiles such as alcohols, water, or ammonia. The high reactivity comes largely from the polar nature of its carbonyl group, where the carbon atom is electrophilic.

As a typical acyl chloride, ethanoyl chloride is an essential participant in nucleophilic acyl substitution reactions. During these reactions, the acyl chloride can be transformed into a variety of derivatives including esters, amides, and anhydrides. In the reaction with nucleophiles like sodium ethoxide, ethanoyl chloride acts as the electrophile that gets attacked.

• Electrophilic character due to the carbonyl group
• Undergoes substitution to form compounds like esters
• Widely used in synthesis of other organic compounds

Ester Formation

Ester formation is a fascinating and fundamental concept in organic chemistry. This process often involves a nucleophilic acyl substitution reaction, whereby an acyl chloride is reacted with an alcohol or its corresponding alkoxide. The example using sodium ethoxide and ethanoyl chloride provides a classic illustration.

In this reaction, the nucleophilic ethoxide ion attacks the electrophilic carbon center of ethanoyl chloride. This results in the displacement of chloride ion and formation of ethyl ethanoate. The resulting ester, ethyl ethanoate \(CH_3COOC_2H_5 \), is an everyday product with a characteristic fruity odor, used in products like nail polish remover and glue.

The hallmark features of ester formation include:

• Occurs through nucleophilic acyl substitution
• Involves the interchange of functional groups
• Produces esters, which are common in natural and synthetic compounds

Understanding ester formation through this reaction can equip students with a stronger grasp on the synthetic capabilities in chemistry.